1997 Buick Park Avenue, 3800, 190,000 miles

My car died on the way home from work about 10 days ago. Checked and replaced battery since it was about 3 to 3.5 years old. Did some more checking and looks like the alternator is bad. Checked output voltage and had the local parts store check it. It was bad. Replaced and about a week later the alt. Died again. We checked it again and it was bad. Replaced wwith a second alt. And checked the voltages on the digital read out and it stays around 12.5 to 13v. I'm thingking there is a fuseable link between the two or the computer module may be killing the alt.